Open AccessHydroxylation of p ‐Coumaric Acid by Illuminated Chloroplasts
Author(s) -
HALLIWELL Barry
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb02169.x
Subject(s) - hydroxylation , chemistry , catalase , superoxide dismutase , chloroplast , benzoic acid , cyanide , enzyme , biochemistry , photochemistry , organic chemistry , gene
1 Chloroplasts isolated from leaves of spinach‐beet ( Beta vulgaris L. ssp. vulgaris ) do not catalyse the hydroxylation of p ‐coumaric acid in the dark unless a reductant (such as ascorbate, NADH or NADPH) is added. Superoxide dismutase has no effect on this reaction. 2 Illuminated chloroplasts catalyse the hydroxylation in the absence of added reductant. This reaction is completely inhibited by superoxide dismutase, but catalase has little effect. 3 Both hydroxylation in the light and hydroxylation in the dark in the presence of reductants are inhibited by diethyldithiocarbamate, EDTA, cyanide and 2‐mercaptoethanol. 4 It is proposed that O 2 .− generated by illuminated chloroplasts is involved in the provision of a reductant to the enzyme phenolase.